Mailer type business forms which utilize pressure sensitive cohesive are becoming increasingly popular. Pressure sensitive cohesive in its commercial form typically is a styrene-natural rubber copolymer composition, such as shown in U.S. Pat. No. 4,918,128 and 5,427,851. Various other forms that the pressure sensitive cohesive may take, including commercial formulations thereof, are disclosed in U.S. Pat. No. 5,201,464 (the disclosure of which is hereby incorporated by herein). In the utilization of the mailer type business form intermediate which includes a pressure cohesive, cooperating patterns of cohesive are provided on cooperating faces of the intermediate which are folded into contact with each other. The mailer so formed is then run through conventional Moore SPEEDISEALER.RTM. pressure seal equipment (as generally illustrated in U.S. Pat. No. 5,397,427) so that a pressure of about 100-200 psi is applied to the cohesive, to provide secure adhesion of the formed panels together. The pressure sensitive cohesive has numerous advantages over conventional heat seal adhesive and reweftable adhesive.
While mailer type business forms with pressure sensitive cohesive are extremely successful, there can be a significant problem in utilization thereof with conventional continuous laser printers. The standard arrangement of pressure sensitive cohesive included in the marginal portions of conventional mailer type business form, such as shown in U.S. Pat. Nos. 5,176,739, 5,174,493, 5,314,110, is elongated strips of cohesive provided in a staggered pattern on the face and the back of the form. This standard staggered pattern was created so that stacked sheets of the product would not block or stick together. However the provision of the cohesive on both faces (front and back) of the sheet can result in flexing of the edges, particularly the long edges (the side, vertical, edges when the sheet is in the "portrait" orientation). This flexing of the vertical edges is called "cupping" or distortion. This distortion can be so excessive at times that the forms cannot feed properly, jam, or cause misfolds on some printers. The problem is compounded because many different paper stocks can be utilized with pressure sensitive cohesive. In addition the cupping on the vertical edges can cause problems in post-processing, including misfeeds, jams, and double feeds. In many post-processing situations the vertical edge of the form is actually the lead edge, such as when processing through a detacher, a transport station, or a folder/sealer (which either V-folds, C-folds, or Z-folds the form and then applies the necessary pressure to activate the cohesive).
According to the present invention, a mailer type business form intermediate is provided which overcomes the cupping problem associated with conventional pressure sensitive cohesive intermediates, so that improper feeding, jamming, and misfolding of the sheet forming the business form intermediate is substantially avoided. This is accomplished according to the present invention by providing a particular pattern of the pressure sensitive adhesive along the vertical edges of the intermediate, preferably in the form of substantially rectangular spots that are spaced apart a distance at least as great as the length thereof, but provide a secure sealing action rather than merely "tacking" the form together. While rectangular spots of pressure sensitive cohesive have been utilized before in business form intermediates (such as shown in U.S. Pat. No. 5,294,041), they have not necessarily been dimensioned or positioned to avoid the cupping problem. Rather they have typically been staggered or spaced so that adhesive on any form length does not contact adhesive on any adjacent form length when the continuous form is fan folded about longitudinal fold lines, which is an approach distinct from that according to the invention.
According to the present invention in the preferred embodiment of the intermediates according to the invention, the pattern which avoids the cupping problem is the provision of a series of substantially rectangular spots of pressure activated adhesive each having a first dimension parallel to the vertical edges of the intermediate of about 0.2-0.3 inches (preferably about 0.25 inches), and a second dimension perpendicular to the first dimension of between about 0.1-0.15 inches (typically about 0.125 inches), with the spots substantially regularly spaced from each other parallel to the vertical edges a distance of between about 1-3 times the first dimension (preferably spaced from each other about twice the first dimension, e.g. about 0.5 inches). Typically at least six spots (and normally about 8-18) are provided on the first face and at least four spots (and normally about 6-12) on the second face. Preferably all of the spots within each margin portion are in a substantially straight line, and may have uniform size and spacing, although if a few spots have a slightly different size or spacing in order to accommodate the requirements of a particular form (such as a spot extending across a fold line, which spot has a first dimension of greater than 0.3 inches but less than about 0.75 inches), cupping problems still can be avoided under most circumstances.
According to one aspect of the present invention a mailer type business form intermediate is provided comprising following conventional components: A substantially quadrate sheet of paper having first and second faces, top and bottom edges substantially parallel to each other, and first and second side edges substantially perpendicular to the top and bottom edges and substantially parallel to each other. The top and bottom edges spaced a first distance, and the side edges spaced a second distance, less than (or equal to) the first distance. First and second lines of weakness formed in the sheet adjacent, but spaced from and substantially parallel to, the first and second side edges, respectively, to define first and second removable side margin portions. A first fold line formed in the sheet substantially parallel to the top and bottom edges, and defining the sheet into panels on opposite sides thereof. What is unique according to the present invention is a pattern of pressure activated cohesive in each of the side margin portions on at least the first face, the patterns for substantially preventing cupping so that improper feeding, jamming, and misfolding of the sheet is substantially avoided. The details of the patterns, comprising series of substantially rectangular spots, is preferably as described above.
Also according to the present invention for many different embodiments (particularly C-folded or Z-folded embodiments) a series of the spots are provided on the second face of the sheet in the margin portions in a same panel as the series of spots in the first face. In this situation the spots on the second face do not significantly overlap the spots on the first face (that is if that they overlap at all it is less than a tenth of an inch). Also according to the present invention the quadrate sheet is typically provided in continuous form format with a second (and more) quadrate sheet substantially identical to the first sheet except for the positioning of the spots, the first and second sheets separated by a line of weakness (such as a perforation line) between the second side edge of the first sheet and the first side edge of the second sheet. The spots on the first face of the second sheet are staggered with respect to the spots on the first face of the first sheet, which facilitates feeding especially in post processing (after passage through a continuous laser printer), and also helps avoid the cupping problem. Separable tractor drive margin portions may be provided adjacent and parallel to the top and bottom edges of each sheet (the tractor drive margin portions are typically cut off with a slitter before mailing of the mailer formed from the intermediate).
First and second longitudinal lines of weakness are also typically provided substantially parallel to and adjacent the top and bottom edges and defining a top and bottom margin in the sheets, and patterns of pressure activated cohesive may be disposed on the top and bottom portions. The patterns in the top and bottom margins may be conventional strips of pressure activated cohesive rather than the spaced spots that are provided in the side margins. The strips of cohesive may be provided on the first face in one of the top and bottom margins, and strips of cohesive on the second face in the other of the top and bottom margins.
Except for intermediates which are designed to be V-folded to produce the mailers, and particularly for C-fold, Z-fold, or double fold intermediates, a second fold line (or other additional fold lines) is provided parallel to the first fold line so that the first and second fold lines define the sheet into at least three panels. Under some circumstances adjacent at least one of the fold line spots may be provided on opposite sides of the fold line in a side margin which are spaced from each other a distance less than the first dimension, or at least one spot in the series in each side margin may extend across a fold line and have a first dimension that is longer than the spots in the series (e.g. greater than 0.3 inches but less than about 0.75 inches). A first series of spots may be provided in the side margins on the first face of the first and second panels, and a second series of spots provided in the side margin on the second face of the second and third panels for Z-folded constructions. The fold lines and the series of spots are provided so that the spots of the series align with each other when the sheet is Z-folded about the fold lines (including eccentrically Z-folded), or C-folded, depending upon the particular construction utilized.
The invention also relates to a method of producing imaged mailers from mailer type business form intermediates such as described above. For example the method may comprise the steps of: Stacking the intermediates in a tray of a laser printer, and feeding the intermediates one at a time from the tray through the laser printer so that the side edges of the intermediate do not cup; imaging at least one face of each of the intermediates; ultimately folding the sheet about the at least one fold line to form a mailer; and then passing each mailer through a pressure sealer to act on the pressure cohesive to apply a sealing pressure of at least about 100 psi to each mailer to seal each intermediate into a mailer.
According to another method of the present invention imaged mailers are produced from mailer type business form intermediates by the steps of: Feeding the intermediates, using the tractor drive holes, one at a time through a continuous laser printer so that the side edges of the intermediate do not cup; imaging at least one face of each of the intermediates; ultimately severing the tractor drive openings from the sheets and separating the sheets from each other, and folding each of the sheets about the at least one fold line to form a mailer; and then passing each mailer through a pressure sealer to act on the pressure cohesive to apply a sealing pressure of at least about 100 psi to each mailer to seal each intermediate into a mailer.
According to yet another aspect of the present invention imaged mailers are produced from mailer type business form intermediates by the steps of: Feeding the intermediates one at a time through a laser printer so that the side edges of the intermediate do not cup; imaging at least one face of each of the intermediates; ultimately Z folding or C folding (eccentrically or non-eccentrically) the sheet about the fold lines to form a mailer; and then passing each mailer through a pressure sealer to act on the pressure cohesive to apply a sealing pressure of at least about 100 psi to each mailer to seal each intermediate into a mailer.
It is the primary object of the present invention to provide advantageous mailer type business form intermediates having pressure activated cohesive, and methods of producing imaged mailers in an advantageous manner from such intermediates. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.